U.S. patent number 10,574,401 [Application Number 16/298,901] was granted by the patent office on 2020-02-25 for polar code retransmission method and apparatus.
This patent grant is currently assigned to HUAWEI TECHNOLOGIES CO., LTD.. The grantee listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Rong Li, Guijie Wang, Jian Wang, Jun Wang, Gongzheng Zhang.
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United States Patent |
10,574,401 |
Li , et al. |
February 25, 2020 |
Polar code retransmission method and apparatus
Abstract
Embodiments of this application provide a polar code
retransmission method and apparatus, to reduce retransmission
complexity and improve transmission performance. The method
includes: determining a first polar channel sequence including N
polar channels and reliability of each of the N polar channels;
determining, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate; determining K.sub.m polar
channels with highest reliability in the first polar channel
sequence; determining K.sub.m information bits based on locations,
of information bits that need to be transmitted during first m-1
data transmissions, in the first polar channel sequence; and
mapping the K.sub.m information bits to the K.sub.m polar channels
for transmission.
Inventors: |
Li; Rong (Hangzhou,
CN), Wang; Guijie (Hangzhou, CN), Zhang;
Gongzheng (Hangzhou, CN), Wang; Jian (Hangzhou,
CN), Wang; Jun (Hangzhou, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Shenzhen, Guangdong |
N/A |
CN |
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Assignee: |
HUAWEI TECHNOLOGIES CO., LTD.
(Shenzhen, Guangdong, CN)
|
Family
ID: |
61561640 |
Appl.
No.: |
16/298,901 |
Filed: |
March 11, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190207720 A1 |
Jul 4, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/CN2017/095827 |
Aug 3, 2017 |
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Foreign Application Priority Data
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Sep 12, 2016 [CN] |
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2016 1 0819549 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
1/1867 (20130101); H04L 1/0057 (20130101); H03M
13/13 (20130101); H04L 1/1819 (20130101); H04L
1/0041 (20130101); H04L 1/1825 (20130101) |
Current International
Class: |
H04L
1/18 (20060101); H04L 1/00 (20060101); H03M
13/13 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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102122966 |
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Jul 2011 |
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CN |
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102164025 |
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Aug 2011 |
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CN |
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102694625 |
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Sep 2012 |
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CN |
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103281166 |
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Sep 2013 |
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CN |
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104243106 |
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Dec 2014 |
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CN |
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105743621 |
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Jul 2016 |
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CN |
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Other References
Bin Li et al.,"Capacity-Achieving Rateless Polar
Codes",arXiv:1508.03112v1 [cs.IT] Aug. 13, 2015,total 14 pages.
cited by applicant.
|
Primary Examiner: Lam; Kenneth T
Attorney, Agent or Firm: Womble Bond Dickinson (US) LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of International
Application No. PCT/CN2017/095827 filed on Aug. 3, 2017, which
claims priority to Chinese Patent Application No. 201610819549.2,
filed on Sep. 12, 2016. The disclosures of the aforementioned
applications are hereby incorporated by reference in their
entireties.
Claims
What is claimed is:
1. A polar code retransmission method, the method comprising:
determining a first polar channel sequence comprising N polar
channels and reliability of each of the N polar channels;
determining, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, wherein the
coding parameter comprises at least one of the quantity of
information bits and a code rate; determining K.sub.m polar
channels with highest reliability in a first polar channel
sequence; determining K.sub.m information bits based on locations,
of information bits that need to be transmitted during first m-1
data transmissions, in the first polar channel sequence; and
mapping the K.sub.m information bits to the K.sub.m polar channels
for transmission; wherein m, K.sub.m, and N are positive integers,
m is greater than 1, and K.sub.m is less than N.
2. The method according to claim 1, wherein m is 2, and the K.sub.m
information bits are information bits that occupy K.sub.m polar
channels with lowest reliability in the first polar channel
sequence during a first data transmission.
3. The method according to claim 1, wherein a code rate of the
first data transmission is R, and a code rate of the m.sup.th data
transmission is ##EQU00033## wherein R is greater than 0 and less
than 1; and determining K.sub.m information bits based on
locations, of information bits that need to be transmitted during
first m-1 data transmissions, in the first polar channel sequence
comprises: determining K.sub.m-1 polar channels, corresponding to
information bits that need to be transmitted during an (m-1).sup.th
data transmission, in the first polar channel sequence, wherein
K.sub.m-1 is less than N and greater than K.sub.m; determining
##EQU00034## polar channels with lowest reliability from the
K.sub.m-1 polar channels; and determining the K.sub.m information
bits from information bits on the ##EQU00035## polar channels
during each of the first m-1 data transmissions.
4. The method according to claim 1, wherein mapping the K.sub.m
information bits to the K.sub.m polar channels for transmission
comprises: sorting the K.sub.m information bits in descending order
of reliability of the polar channels corresponding to the K.sub.m
information bits that need to be transmitted during the first data
transmission; and mapping, for transmission, the sorted K.sub.m
information bits to the K.sub.m polar channels ranked in descending
order of reliability.
5. The method according to claim 1, wherein before determining,
based on a coding parameter for an m.sup.th data transmission, a
quantity K.sub.m of information bits that need to be transmitted
during the m.sup.th data transmission, the method further
comprises: determining the coding parameter for the m.sup.th data
transmission.
6. The method according to claim 5, wherein determining the coding
parameter for the m.sup.th data transmission comprises: determining
a preset coding parameter as the coding parameter for the m.sup.th
data transmission.
7. The method according to claim 5, wherein determining the coding
parameter for the m.sup.th data transmission comprises: receiving
feedback information sent by a receive device for the (m-1).sup.th
data transmission; and determining the coding parameter for the
m.sup.th data transmission based on the feedback information for
the (m-1).sup.th data transmission.
8. The method according to claim 1, wherein the first polar channel
sequence is generated by sorting the N polar channels based on the
reliability of each of the N polar channels.
9. A polar code retransmission method, the method comprising:
determining a first polar channel sequence comprising N polar
channels and reliability of each of the N polar channels;
determining, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, wherein the
coding parameter comprises at least one of the quantity of
information bits and a code rate; determining K.sub.m polar
channels with highest reliability in the first polar channel
sequence; and decoding, on the K.sub.m polar channels, data
transmitted during the m.sup.th data transmission; wherein m,
K.sub.m, and N are positive integers, m is greater than 1, and
K.sub.m is less than N.
10. The method according to claim 9, wherein the first polar
channel sequence is generated by sorting the N polar channels based
on the reliability of each of the N polar channels.
11. The method according to claim 9, wherein the method further
comprises: sending feedback information to a transmit device for
determining the coding parameter for the m.sup.th data transmission
based on the feedback information.
12. The method according to claim 9, wherein the reliability of
each polar channel is a polarization weight of the polar
channel.
13. The method according to claim 12, wherein before determining a
first polar channel sequence comprising of N polar channels and
reliability of each of the N polar channels, the method further
comprises: calculating the polarization weight of each of the N
polar channels.
14. The method according to claim 13, wherein calculating the
polarization weights of the N polar channels comprises: obtaining
the first polarization weight vector by calculating the
polarization weights W.sub.i of the N polar channels according to
the following formula: .times..PHI..alpha. ##EQU00036## where
iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
15. A polar code retransmission apparatus, comprising: a
transceiver; a memory, configured to store one or more
instructions; a processor, separately coupled to the memory and the
transceiver, and configured to execute the one or more instructions
stored in the memory to cause the apparatus to: determine a first
polar channel sequence comprising of N polar channels and
reliability of each of the N polar channels; determine, based on a
coding parameter for an m.sup.th data transmission, a quantity
K.sub.m of information bits that need to be transmitted during the
m.sup.th data transmission, wherein the coding parameter comprises
at least one of the quantity of information bits and a code rate;
determine K.sub.m polar channels with highest reliability in the
first polar channel sequence; and decode, on the K.sub.m polar
channels, data transmitted during the m.sup.th data transmission;
wherein m, K.sub.m, and N are positive integers, m is greater than
1, and K.sub.m is less than N.
16. The apparatus according to claim 15, wherein the first polar
channel sequence is generated by sorting the N polar channels based
on the reliability of each of the N polar channels.
17. The apparatus according to claim 15, wherein the transceiver is
further configured to: send feedback information to a transmit
device for determining the coding parameter for the m.sup.th data
transmission based on the feedback information.
18. The apparatus according to claim 15, wherein the reliability of
each polar channel is a polarization weight of the polar
channel.
19. The apparatus according to claim 18, wherein the processor is
configured to execute the one or more instructions to cause the
apparatus to: before the first polar channel sequence comprising
the N polar channels and the reliability of each of the N polar
channels are determined, calculate the polarization weight of each
of the N polar channels.
20. The apparatus according to claim 19, wherein the processor is
configured to execute the one or more instructions to cause the
apparatus to: obtain a first polarization weight vector by
calculating the polarization weights W of the N polar channels
according to the following formula: .times..PHI..alpha.
##EQU00037## where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a
channel index, B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary
representation of i, B.sub.n-1 is a most significant bit, B.sub.0
is a least significant bit, B.sub.j.di-elect cons.{0,1}, j.di-elect
cons.{0, 1, . . . , n-1}, i.di-elect cons.{0, 1, . . . , n-1},
N=2.sup.n, .PHI. and .alpha. are parameters preset based on a
target code length of a first data transmission and a code rate of
the first data transmission, and n is a positive integer.
Description
TECHNICAL FIELD
This application relates to the communications field, and more
specifically, to a polar code retransmission method and
apparatus.
BACKGROUND
In a communications system, usually data transmission reliability
is improved through channel encoding, to ensure communication
quality. A polar code (polar code) is an encoding manner that can
achieve a Shannon capacity and that has low encoding and decoding
complexity. The polar code is a linear block code. A generation
matrix of the polar code is G.sub.N, and an encoding process of the
polar code is x.sub.1.sup.N=u.sub.1.sup.NG.sub.N, where
u.sub.1.sup.N=(u.sub.1, u.sub.2, . . . , u.sub.N) is a binary row
vector, G.sub.N=B.sub.NF.sub.2.sup.(log.sup.2.sup.(N)), a code
length N=2.sup.n, and n.gtoreq.0.
##EQU00001## and B.sub.N is an N.times.N transposed matrix, such as
a bit reversal matrix. F.sub.2.sup.(log.sup.2.sup.(N)) is a
Kronecker power of F.sub.2, and is defined as
F.sup.(log.sup.2.sup.(N))=FF.sup.((log.sup.2.sup.(N))-1).
In the encoding process of the polar code, some bits in
u.sub.1.sup.N are used to carry information and are referred to as
information bits, and a sequence number set of these information
bits is denoted as A. The other bits are set to fixed values that
are agreed on by a transmit end and a receive end in advance and
are referred to as fixed bits, and a sequence number set of these
bits is represented by using a complementary set A.sup.c of A.
Without loss of generality, these fixed bits are usually set to 0.
Actually, a fixed bit sequence may be randomly set provided that
the transmit end and the receive end agree in advance. Therefore,
an encoded bit sequence of the polar code may be obtained by using
the following method: x.sub.1.sup.N=u.sub.AG.sub.N(A), where
u.sub.A is an information bit set in u.sub.1.sup.N, and u.sub.A is
a row vector of a length K, in other words, |A|=K, | | indicates a
quantity of elements in the set, and K indicates a quantity of
elements in the set A and also indicates a quantity of
to-be-encoded information bits; and G.sub.N(A) is a submatrix that
is in the matrix G.sub.N and that is obtained based on rows
corresponding to indexes in the set A, and G.sub.N(A) is a
K.times.N matrix. Selection of the set A determines performance of
the polar code.
In communications application that is insensitive to a system
latency, a hybrid automatic repeat request (HARQ) is a commonly
used transmission method for improving a system throughput. When
transmitting an information block, a transmit device encodes the
information block and sends the encoded information block to a
channel. If a receive device decodes a received signal and finds
that transmission succeeds, the receive device sends an
acknowledgement (ACK) message to the transmit device, so as to
complete the transmission of the information block. If the receive
device decodes a received signal and finds that transmission fails
(for example, cyclic redundancy check fails), the receive device
transmits a negative acknowledgement (NACK) message to the transmit
device through a feedback link, and the transmit device retransmits
the information block. Alternatively, when no ACK feedback sent by
the receive device is received within a specific period of time,
the transmit device also retransmits the information block. This
process continues until the receive device correctly performs
decoding. To obtain a maximum link throughput, the receive device
temporarily stores all received signals and decodes the received
signals together with a newly received signal.
In an existing retransmission method, reliability of a polar
channel needs to be recalculated based on a current code rate
during each retransmission, and complexity is excessively high.
SUMMARY
In view of the above, embodiments of this application provide a
polar code (polar code) retransmission method, to reduce
retransmission complexity and improve transmission performance.
According to a first aspect, a polar code retransmission method is
provided, including: determining a first polar channel sequence
including N polar channels and reliability of each of the N polar
channels; determining, based on a coding parameter for an m.sup.th
data transmission, a quantity K.sub.m of information bits that need
to be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate; determining K.sub.m polar
channels with highest reliability in the first polar channel
sequence; determining K.sub.m information bits based on locations,
of information bits that need to be transmitted during first m-1
data transmissions, in the first polar channel sequence; and
mapping the K.sub.m information bits to the K.sub.m polar channels
for transmission, where m, K.sub.m, and N are positive integers, m
is greater than 1, and K.sub.m is less than N.
Specifically, a transmit device may determine the first polar
channel sequence based on the reliability of each of the N polar
channels, and adjust information bits based on the first polar
channel sequence during each subsequent data transmission. In
addition, before each data transmission, the transmit device first
needs to determine a coding parameter for this data transmission.
It should be understood that the coding parameter may include at
least one of the following parameters: a code length (which may
also be referred to as a quantity of encoded bits), a quantity of
information bits, and a code rate. After determining the coding
parameter for this transmission, the transmit device determines,
based on the coding parameter, a quantity K.sub.m of information
bits that need to be transmitted, and then selects corresponding
K.sub.m polar channels and K.sub.m information bits to perform
mapping and transmission. In this embodiment of this application,
when performing the m.sup.th data transmission, the transmit device
determines K.sub.m information bits used for the m.sup.th data
transmission, and maps the K.sub.m information bits to K.sub.m
polar channels with highest reliability for encoding and
transmission.
Therefore, according to the polar code retransmission method in
this embodiment of this application, the same polar channel
sequence is used during each data transmission, and the determined
K.sub.m information bits are directly mapped to the K.sub.m polar
channels with highest reliability in the polar channel sequence for
transmission, without recalculating the reliability of the polar
channels before each retransmission. This can reduce retransmission
complexity and improve transmission performance, thereby improving
user experience.
It should be understood that the reliability of the polar channels
may be calculated through density evolution (DE) or Gaussian
approximation (GA).
In a first possible implementation of the first aspect, m is 2, and
the K.sub.m information bits are information bits that occupy
K.sub.m polar channels with lowest reliability in the first polar
channel sequence during a first data transmission.
Specifically, during a retransmission, the transmit device may
select information bits transmitted on polar channels with lowest
reliability during the first data transmission, and select K.sub.m
information bits with lowest reliability that are corresponding to
the polar channels to perform the retransmission. In this way, a
decoding success rate of a receive device can be increased, and a
quantity of retransmissions of the transmit device can be
reduced.
With reference to the foregoing possible implementation of the
first aspect, in a second possible implementation of the first
aspect, a code rate of the first data transmission is R, and a code
rate of the m.sup.th data transmission is
##EQU00002## where R is greater than 0 and less than 1; and the
determining K.sub.m information bits based on locations, of
information bits that need to be transmitted during first m-1 data
transmissions, in the first polar channel sequence includes:
determining K.sub.m-1 polar channels, corresponding to information
bits that need to be transmitted during an (m-1).sup.th data
transmission, in the first polar channel sequence, where K.sub.m-1
is less than N and greater than K.sub.m; determining
##EQU00003## polar channels with lowest reliability from the
K.sub.m-1 polar channels; and determining the K.sub.m information
bits from information bits on the
##EQU00004## polar channels during each of the first m-1 data
transmissions.
Specifically, before performing the m.sup.th data transmission, the
transmit device may first determine the
##EQU00005## polar channels, with lowest reliability corresponding
to the information bits that need to be transmitted during the
(m-1).sup.th data transmission, in the first polar channel
sequence, and then select the K.sub.m information bits from
information bits mapped to the
##EQU00006## polar channels during each of the first m-1 data
transmissions, to perform the m.sup.th data transmission.
Therefore, information bits corresponding to most unreliable polar
channels during all previous data transmissions are comprehensively
considered, and the information bits are mapped to K.sub.m polar
channels with highest reliability for retransmission, so as to
enhance reliability of these most unreliable information bits, and
increase a decoding success rate.
With reference to the foregoing possible implementations of the
first aspect, in a third possible implementation of the first
aspect, the mapping the K.sub.m information bits to the K.sub.m
polar channels for transmission includes: sorting the K.sub.m
information bits in descending order of reliability of the polar
channels corresponding to the K.sub.m information bits that need to
be transmitted during the first data transmission; and mapping, for
transmission, the sorted K.sub.m information bits to the K.sub.m
polar channels ranked in descending order of reliability.
Specifically, during each retransmission, the K.sub.m information
bits may be mapped, in descending order of the reliability of the
polar channels occupied by the K.sub.m information bits during the
first data transmission, to the K.sub.m polar channels ranked in
descending order of reliability.
With reference to the foregoing possible implementations of the
first aspect, in a fourth possible implementation of the first
aspect, before the determining, based on a coding parameter for an
m.sup.th data transmission, a quantity K.sub.m of information bits
that need to be transmitted during the m.sup.th data transmission,
the method further includes: determining the coding parameter for
the m.sup.th data transmission.
Specifically, the transmit device may determine the coding
parameter for the m.sup.th data transmission in a plurality of
manners. Specifically, the coding parameter may be agreed on by the
transmit device and the receive device in advance, or may be
determined by the transmit device based on feedback information
from the receive device before each retransmission. This is not
limited in this embodiment of this application.
With reference to the foregoing possible implementations of the
first aspect, in a fifth possible implementation of the first
aspect, the determining the coding parameter for the m.sup.th data
transmission includes: determining a preset coding parameter as the
coding parameter for the m.sup.th data transmission.
In a specific implementation, a code rate of an initial
transmission may be R, a code rate of a second transmission is
##EQU00007## a code rate of a third transmission is
##EQU00008## . . . , and a code rate of the m.sup.th transmission
is
##EQU00009##
With reference to the foregoing possible implementations of the
first aspect, in a sixth possible implementation of the first
aspect, the determining the coding parameter for the m.sup.th data
transmission includes: receiving feedback information sent by a
receive device for the (m-1).sup.th data transmission; and
determining the coding parameter for the m.sup.th data transmission
based on the feedback information for the (m-1).sup.th data
transmission.
In this way, the transmit device can adjust, by using the feedback
information sent by the receive device, a coding parameter such as
a code rate, a code length, or a quantity of information bits, so
as to adaptively change a code rate during a retransmission.
With reference to the foregoing possible implementations of the
first aspect, in a seventh possible implementation of the first
aspect, the first polar channel sequence is generated by sorting
the N polar channels based on the reliability of each of the N
polar channels.
In this way, the transmit device does not need to determine a
reliability value of each of the N polar channels during each
transmission, but only needs to obtain the first polar channel
sequence obtained after the N polar channels are sorted based on
reliability values. This reduces complexity and improves coding
efficiency.
With reference to the foregoing possible implementations of the
first aspect, in an eighth possible implementation of the first
aspect, the reliability of each polar channel is a polarization
weight of the polar channel.
With reference to the foregoing possible implementations of the
first aspect, in a ninth possible implementation of the first
aspect, before the determining a first polar channel sequence
including N polar channels and reliability of each of the N polar
channels, the method further includes: calculating the polarization
weight of each of the N polar channels.
With reference to the foregoing possible implementations of the
first aspect, in a tenth possible implementation of the first
aspect, the calculating the polarization weight of each of the N
polar channels includes: obtaining a first polarization weight
vector by calculating the polarization weights W.sub.i of the N
polar channels according to the following formula:
.times..PHI..alpha. ##EQU00010##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of the
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
According to a second aspect, a polar code retransmission method is
provided, including: determining a first polar channel sequence
including N polar channels and reliability of each of the N polar
channels; determining, based on a coding parameter for an m.sup.th
data transmission, a quantity K.sub.m of information bits that need
to be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate; determining K.sub.m polar
channels with highest reliability in the first polar channel
sequence; and decoding, on the K.sub.m polar channels, data
transmitted during the m.sup.th data transmission, where m,
K.sub.m, and N are positive integers, m is greater than 1, and
K.sub.m is less than N.
Therefore, according to the polar code retransmission method in
this embodiment of this application, during each data transmission,
K.sub.m polar channels are directly determined by using the same
polar channel sequence, and received data is directly decoded on
the K.sub.m polar channels, without recalculating reliability of
the polar channels before each reception of data retransmitted by a
transmit device. This can reduce decoding complexity and improve
transmission performance, thereby improving user experience.
In a first possible implementation of the second aspect, the first
polar channel sequence is generated by sorting the N polar channels
based on the reliability of each of the N polar channels.
With reference to the foregoing possible implementation of the
second aspect, in a second possible implementation of the second
aspect, the method further includes: sending feedback information
to a transmit device, so that the transmit device determines the
coding parameter for the m.sup.th data transmission based on the
feedback information.
With reference to the foregoing possible implementations of the
second aspect, in a third possible implementation of the second
aspect, the reliability of each polar channel is a polarization
weight of the polar channel.
With reference to the foregoing possible implementations of the
second aspect, in a fourth possible implementation of the second
aspect, before the determining a first polar channel sequence
including N polar channels and reliability of each of the N polar
channels, the method further includes: calculating the polarization
weight of each of the N polar channels.
With reference to the foregoing possible implementations of the
second aspect, in a fifth possible implementation of the second
aspect, the calculating the polarization weight of each of the N
polar channels includes: obtaining a first polarization weight
vector by calculating the polarization weights W.sub.i of the N
polar channels according to the following formula:
.times..PHI..alpha. ##EQU00011##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
According to a third aspect, a polar code retransmission apparatus
is provided, configured to perform the method in any one of the
first aspect or the possible implementations of the first aspect.
Specifically, the apparatus includes units configured to perform
the method in any one of the first aspect or the possible
implementations of the first aspect.
According to a fourth aspect, a polar code retransmission apparatus
is provided, configured to perform the method in any one of the
second aspect or the possible implementations of the second aspect.
Specifically, the apparatus includes units configured to perform
the method in any one of the second aspect or the possible
implementations of the second aspect.
According to a fifth aspect, a polar code retransmission apparatus
is provided. The apparatus includes a receiver, a transmitter, a
memory, a processor, and a bus system. The receiver, the
transmitter, the memory, and the processor are connected to each
other by using the bus system. The memory is configured to store an
instruction. The processor is configured to execute the instruction
stored in the memory, to control the receiver to receive a signal
and control the transmitter to send a signal. In addition, when the
processor executes the instruction stored in the memory, the
execution enables the processor to perform the method in any one of
the first aspect or the possible implementations of the first
aspect.
According to a sixth aspect, a polar code retransmission apparatus
is provided. The apparatus includes a receiver, a transmitter, a
memory, a processor, and a bus system. The receiver, the
transmitter, the memory, and the processor are connected to each
other by using the bus system. The memory is configured to store an
instruction. The processor is configured to execute the instruction
stored in the memory, to control the receiver to receive a signal
and control the transmitter to send a signal. In addition, when the
processor executes the instruction stored in the memory, the
execution enables the processor to perform the method in any one of
the second aspect or the possible implementations of the second
aspect.
According to a seventh aspect, a polar code retransmission system
is provided, where the system includes the apparatus in any one of
the third aspect or the possible implementations of the third
aspect and the apparatus in any one of the fourth aspect or the
possible implementations of the fourth aspect; or the system
includes the apparatus in any one of the fifth aspect or the
possible implementations of the fifth aspect and the apparatus in
any one of the sixth aspect or the possible implementations of the
sixth aspect.
According to an eighth aspect, a computer-readable medium is
provided, and is configured to store a computer program, and the
computer program includes instructions used to perform the method
in any one of the first aspect or the possible implementations of
the first aspect.
According to a ninth aspect, a computer-readable medium is
provided, and is configured to store a computer program, and the
computer program includes instructions used to perform the method
in any one of the second aspect or the possible implementations of
the second aspect.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an application scenario according
to an embodiment of this application;
FIG. 2 is a schematic flowchart of a polar code retransmission
method according to an embodiment of this application;
FIG. 3 is a schematic flowchart of another polar code
retransmission method according to an embodiment of this
application;
FIG. 4 is a schematic flowchart of another polar code
retransmission method according to an embodiment of this
application;
FIG. 5 is a schematic flowchart of another polar code
retransmission method according to an embodiment of this
application;
FIG. 6 is a schematic block diagram of a polar code retransmission
apparatus according to an embodiment of this application;
FIG. 7 is a schematic block diagram of another polar code
retransmission apparatus according to an embodiment of this
application;
FIG. 8 is a schematic block diagram of another polar code
retransmission apparatus according to an embodiment of this
application;
FIG. 9 is a schematic block diagram of another polar code
retransmission apparatus according to an embodiment of this
application;
FIG. 10 is a schematic diagram of transmission performance of a
polar code retransmission method according to an embodiment of this
application; and
FIG. 11 is a schematic diagram of transmission performance of
another polar code retransmission method according to an embodiment
of this application.
DETAILED DESCRIPTION
The following describes the technical solutions in the embodiments
of this application with reference to accompanying drawings of the
embodiments of this application.
The embodiments of this application may be applied to various
communications systems. Therefore, the following descriptions are
not limited to a particular communications system. For example, the
communications system may be a Global System for Mobile
Communications (GSM), a Code Division Multiple Access (CDMA)
system, a Wideband Code Division Multiple Access (WCDMA) system, a
general packet radio service (GPRS) system, a Long Term Evolution
(LTE) system, an LTE frequency division duplex (FDD) system, an LTE
time division duplex (TDD) system, or a Universal Mobile
Telecommunications System (UMTS). All information or data encoded
by a base station or a terminal in the foregoing system by using a
conventional turbo code and LDPC code can be encoded by using a
polar code in the embodiments.
The base station may be a device for communication with the
terminal. For example, the base station may be a base transceiver
station (BTS) in a GSM or CDMA system, or may be a NodeB (NB) in a
WCDMA system, or may be an evolved NodeB (eNB or eNodeB) in an LTE
system. Alternatively, the base station may be a relay node, an
access point, an in-vehicle device, a wearable device, a
network-side device in a future 5G network, or the like.
The terminal may communicate with one or more core networks through
a radio access network (RAN). The terminal may be user equipment
(UE), an access terminal, a subscriber unit, a subscriber station,
a mobile station, a mobile console, a remote station, a remote
terminal, a mobile device, a user terminal, a wireless
communications device, a user agent, or a user apparatus. The
access terminal may be a cellular phone, a cordless phone, a
Session Initiation Protocol (SIP) phone, a wireless local loop
(WLL) station, a personal digital assistant (PDA), a handheld
device having a wireless communication function, a computing
device, another processing device connected to a wireless modem, an
in-vehicle device, a wearable device, a terminal in a future 5G
network, or the like.
FIG. 1 shows a wireless communications system 100 according to the
embodiments of this specification. The system 100 includes a base
station 102, and the base station 102 may include a plurality of
antenna groups. For example, one antenna group may include an
antenna 104 and an antenna 106, another antenna group may include
an antenna 108 and an antenna 110, and an additional group may
include an antenna 112 and an antenna 114. Two antennas are shown
for each antenna group; however, each group may have more or fewer
antennas. The base station 102 may additionally include a
transmitter chain and a receiver chain. A person of ordinary skill
in the art may understand that the transmitter chain and the
receiver chain each may include a plurality of components, such as
a processor, a modulator, a multiplexer, a demodulator, a
demultiplexer, or an antenna related to signal transmission and
reception.
The base station 102 may communicate with one or more access
terminals, such as an access terminal 116 and an access terminal
122. However, it may be understood that the base station 102 may
communicate with almost any quantity of access terminals similar to
the access terminal 116 and the access terminal 122. The access
terminal 116 and the access terminal 122 may be, for example,
cellular phones, smartphones, portable computers, handheld
communications devices, handheld computing devices, satellite radio
apparatuses, devices related to the Global Positioning Systems,
PDAs, and/or any other appropriate devices used for communication
in the wireless communications system 100. As shown in the figure,
the access terminal 116 communicates with the antenna 112 and the
antenna 114. The antenna 112 and the antenna 114 send information
to the access terminal 116 through a forward link 118, and receive
information from the access terminal 116 through a reverse link
120. In addition, the access terminal 122 communicates with the
antenna 104 and the antenna 106. The antenna 104 and the antenna
106 send information to the access terminal 122 through a forward
link 124, and receive information from the access terminal 122
through a reverse link 126. In a frequency division duplex (FDD)
system, for example, the forward link 118 may use a frequency band
different from that used by the reverse link 120, and the forward
link 124 may use a frequency band different from that used by the
reverse link 126. In addition, in a time division duplex (TDD)
system, the forward link 118 and the reverse link 120 may use a
same frequency band, and the forward link 124 and the reverse link
126 may use a same frequency band.
Each antenna group or each area or both designed for communication
are referred to as sectors of the base station 102. For example,
the antenna group may be designed to communicate with an access
terminal in a sector in a coverage area of the base station 102.
During communication through the forward link 118 and the forward
link 124, a transmit antenna of the base station 102 may increase
signal-to-noise ratios of the forward link 118 for the access
terminal 116 and the forward link 124 for the access terminal 122
through beamforming. In addition, compared with a case in which a
base station performs sending to all access terminals of the base
station by using a single antenna, when the base station 102
performs, through beamforming, sending to the access terminal 116
and the access terminal 122 that are randomly scattered in the
related coverage area, less interference is caused to a mobile
device in a neighboring cell.
At a given time, the base station 102, the access terminal 116,
and/or the access terminal 122 may be wireless communications
sending apparatuses and/or wireless communications receiving
apparatuses. When sending data, a wireless communications sending
apparatus may encode the data for transmission. Specifically, the
wireless communications sending apparatus may have (for example,
generate, obtain, or store in a memory) a specific quantity of
information bits that need to be sent to the wireless
communications receiving apparatus over a channel. The information
bits may be included in a transport block or a plurality of
transport blocks of data, and the transport block may be segmented
to generate a plurality of code blocks. In addition, the wireless
communications sending apparatus may encode each code block by
using a polar encoder, so as to improve data transmission
reliability, thereby ensuring communication quality.
FIG. 2 is a schematic flowchart of a polar code retransmission
method 200 according to an embodiment of this application. The
method 200 may be applied to the wireless communications system 100
in FIG. 1. However, this embodiment of this application is not
limited thereto. In addition, the method 200 may be performed by a
network device, or may be user equipment. As shown in FIG. 2, the
method 200 includes the following steps:
S210. Determine a first polar channel sequence including N polar
channels and reliability of each of the N polar channels.
S220. Determine, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate.
S230. Determine K.sub.m polar channels with highest reliability in
the first polar channel sequence.
S240. Determine K.sub.m information bits based on locations, of
information bits that need to be transmitted during first m-1 data
transmissions, in the first polar channel sequence.
S250. Map the K.sub.m information bits to the K.sub.m polar
channels for transmission.
Herein, m, K.sub.m, and N are positive integers, m is greater than
1, and K.sub.m is less than N.
Specifically, a transmit device may determine the first polar
channel sequence based on the reliability of each of the N polar
channels, and adjust information bits based on the first polar
channel sequence during each subsequent data transmission. In
addition, before each data transmission, the transmit device first
needs to determine a coding parameter for this data transmission.
It should be understood that the coding parameter may include at
least one of the following parameters: a code length (which may
also be referred to as a quantity of encoded bits), a quantity of
information bits, and a code rate. After determining the coding
parameter for this transmission, the transmit device determines,
based on the coding parameter, a quantity K.sub.m of information
bits that need to be transmitted, and then selects corresponding
K.sub.m polar channels and K.sub.m information bits to perform
mapping and transmission. In this embodiment of this application,
when performing the m.sup.th data transmission, the transmit device
determines K.sub.m information bits used for the m.sup.th data
transmission, and maps the K.sub.m information bits to K.sub.m
polar channels with highest reliability for encoding and
transmission.
In this way, the K.sub.m polar channels used for the m.sup.th data
transmission are all selected based on the first polar channel
sequence. To be specific, a polar channel sequence occupied by
information bits that need to be transmitted during a second data
transmission is a sub-sequence of the first polar channel sequence,
a polar channel sequence occupied by information bits that need to
be transmitted during a third data transmission is also a
sub-sequence of the first polar channel sequence, and so on. A
polar channel sequence occupied by information bits that need to be
transmitted during each subsequent retransmission is a sub-sequence
determined based on the first polar channel sequence.
It should be understood that data transmissions may require a same
quantity of information bits or different quantities of information
bits. For example, when m=2, a quantity of information bits that
need to be transmitted during a second data transmission is
K.sub.2; when m=3, a quantity of information bits that need to be
transmitted during a third data transmission is K.sub.3, . . . ,
where K.sub.2 and K.sub.3 may be equal or not equal. In an
implementation, K.sub.3 is less than K.sub.2, in other words, for
the m.sup.th data transmission, K.sub.m is less than
K.sub.m-.sub.1. However, this embodiment of this application is not
limited thereto.
It should be further understood that, before an initial data
transmission is performed, the transmit device may obtain the
reliability of each of the N polar channels, and when performing a
subsequent retransmission, the transmit device selects at least one
polar channel with highest reliability based on the previously
obtained reliability of each polar channel. Specifically, the
reliability of the polar channels may be calculated through density
evolution (DE) or Gaussian approximation (GA).
Therefore, according to the polar code retransmission method in
this embodiment of this application, the same polar channel
sequence is used during each data transmission, and the determined
K.sub.m information bits are directly mapped to the K.sub.m polar
channels with highest reliability in the polar channel sequence for
transmission, without recalculating the reliability of the polar
channels before each retransmission. This can reduce retransmission
complexity and improve transmission performance, thereby improving
user experience.
That the transmit device needs to perform the m.sup.th data
transmission means that after the (m-1).sup.th data transmission is
performed, the transmit device needs to perform the m.sup.th data
transmission after a receive device fails to decode data
transmitted during the (m-1).sup.th transmission. Specifically, the
transmit device may acknowledge, according to received negative
acknowledgement (NACK) information, that the receive device fails
to decode the data.
It should be understood that m is not equal to 1, and the foregoing
embodiment represents each retransmission process. During an
initial transmission, if the transmit device is user equipment, the
user equipment may determine information such as a code rate and a
quantity of information bits that need to be transmitted during the
transmission by receiving scheduling information of a base station,
for example, by receiving indication information sent by the base
station. The indication information may include a modulation and
coding scheme (MCS) and a quantity of resource blocks (RBs). The
transmit device determines the code rate, a quantity of encoded
bits, and the quantity of information bits that need to be
transmitted during the initial transmission based on the indication
information. In another case without scheduling, the transmit
device obtains the foregoing coding parameter based on information
such as an available transmission resource, an agreed code rate,
and a modulation order.
In an optional embodiment, the reliability of each polar channel is
a polarization weight of the polar channel.
Specifically, the polarization weight is a broad concept, and is
not limited to a single construction method. For different polar
code construction manners, different methods are used for
calculating a polarization weight. This is not limited in this
embodiment of this application.
In a specific implementation, for a polar code with a code length
of 2 raised to the power of n, that is, N=2.sup.n, N to-be-encoded
bits include information bits and frozen bits. First, it is
determined, based on the code length N, that there are N polar
channels in total with channel sequence numbers 0 to N-1. The polar
channel sequence numbers are used as parameters, to perform
operations sequentially, and calculate a polarization weight W of
each of the N polar channels. All the polar channels are sorted in
descending order of the polarization weights, the first K.sub.m
polar channels are selected, and sequence numbers of the first
K.sub.m polar channels are used as a location set for placing the
K.sub.m information bits (to-be-encoded bits). After the K.sub.m
information bits are placed in the previously selected location
set, bits on other locations are set as frozen bits, to obtain a
complete to-be-encoded bit sequence with a length of N. Finally, an
encoding process of the to-be-encoded bit sequence is completed by
using an encoding matrix G.sub.N of the polar code.
Specifically, the first polarization weight vector is obtained by
calculating the polarization weights W.sub.i of the N polar
channels according to the following formula:
.times..PHI..alpha. ##EQU00012##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
In an optional embodiment, the first polar channel sequence is
generated by sorting the N polar channels based on the reliability
of each of the N polar channels.
Specifically, after obtaining the reliability of each of the N
polar channels, the transmit device may sort the N polar channels
based on the reliability of each polar channel. The sorting may be
performed in ascending order or in descending order of reliability.
This is not limited in this embodiment of this application. After
rankings of the reliability of the N polar channels are determined,
the determined information bits may be directly mapped to polar
channels with highest rankings for transmission during each
retransmission. In this way, the transmit device does not need to
determine a reliability value of each of the N polar channels
during each transmission, but only needs to obtain the first polar
channel sequence obtained after the N polar channels are sorted
based on reliability values. This reduces complexity and improves
coding efficiency.
In an optional embodiment, m is 2, and the K.sub.m information bits
are information bits that occupy K.sub.m polar channels with lowest
reliability in the first polar channel sequence during the first
data transmission.
Specifically, during a retransmission, the transmit device may
select information bits transmitted on polar channels with lowest
reliability during the first data transmission, and select K.sub.m
information bits that are corresponding to the polar channels with
lowest reliability to perform the retransmission. In this way, a
decoding success rate of the receive device can be increased, and a
quantity of retransmissions of the transmit device can be
reduced.
In an optional embodiment, a code rate of the first data
transmission is R, and a code rate of the m.sup.th data
transmission is
##EQU00013## where R is greater than 0 and less than 1.
The determining K.sub.m information bits based on locations, of
information bits that need to be transmitted during first m-1 data
transmissions, in the first polar channel sequence includes:
determining K.sub.m-1 polar channels, corresponding to information
bits that need to be transmitted during an (m-1).sup.th data
transmission, in the first polar channel sequence, where K.sub.m-1
is less than N and greater than K.sub.m;
determining
##EQU00014## polar channels with lowest reliability from the
K.sub.m-1 polar m-1 channels; and
determining the K.sub.m information bits from information bits on
the
##EQU00015## polar channels during each of the first m-1 data
transmissions.
Specifically, before performing the m.sup.th data transmission, the
transmit device may first determine the information bits used
during the (m-1).sup.th data transmission, determine the polar
channels occupied by these information bits in the first polar
channel sequence during the (m-1).sup.th data transmission,
determine the
##EQU00016## polar channels with lowest reliability from these
polar channels, and then select the K.sub.m information bits from
information bits mapped to the
##EQU00017## polar channels during each of the first m-1 data
transmissions, to perform the m.sup.th data transmission.
For example, if the transmit device is to perform a third data
transmission, and a quantity of information bits that need to be
transmitted during a first transmission is 12, according to a
regularity of a code rate, a quantity of information bits that need
to be transmitted during the third data transmission is 4, and is
corresponding to four polar channels with highest reliability. The
transmit device may first select six information bits that need to
be transmitted during a second data transmission, then determine
six polar channels corresponding to the six information bits,
determine two polar channels with lowest reliability from the six
polar channels, and then use two information bits transmitted on
the two polar channels during the first data transmission and two
information bits transmitted on the two polar channels during the
second data transmission as four information bits that need to be
transmitted during the third data transmission.
It should be understood that, when K.sub.m is indivisible by
m-1,
##EQU00018## polar channels first need to be determined; then,
.times. ##EQU00019## information bits mapped to the
##EQU00020## polar channels during each of the first m-1 data
transmissions are determined, where
.times. ##EQU00021## is greater than K.sub.m; and finally, K.sub.m
information bits are selected from the
.times. ##EQU00022## information bits as information bits, for the
m.sup.th data transmission, mapped to the K.sub.m polar channels.
Optionally, an information bit on a polar channel with low
reliability may be selected based on locations, occupied by the
.times. ##EQU00023## information bits, in the first polar channel
sequence during a previous data transmission. This is not limited
in this embodiment of this application.
Therefore, information bits corresponding to most unreliable polar
channels during all previous data transmissions are comprehensively
considered, and the information bits are mapped to polar channels
with highest reliability for retransmission, so as to enhance
reliability of these most unreliable information bits, and increase
a decoding success rate.
It should be understood that rankings of the K.sub.m information
bits on the K.sub.m polar channels with highest reliability in the
first polar channel sequence are not unique, and may be rankings of
the K.sub.m information bits used during the first transmission, or
may be any other rankings. This is not limited in this embodiment
of this application.
In an optional embodiment, the mapping the K.sub.m information bits
to the K.sub.m polar channels for transmission includes:
sorting the K.sub.m information bits in descending order of
reliability of the polar channels corresponding to the K.sub.m
information bits that need to be transmitted during the first data
transmission; and
mapping, for transmission, the sorted K.sub.m information bits to
the K.sub.m polar channels ranked in descending order of
reliability.
Specifically, during each retransmission, the K.sub.m information
bits may be mapped, in descending order of the reliability of the
polar channels occupied by the K.sub.m information bits during the
first data transmission, to the K.sub.m polar channels ranked in
descending order of reliability.
Specifically, FIG. 3 is a schematic flowchart of another polar code
retransmission method according to an embodiment of this
application. As shown in FIG. 3, a first data transmission, a
second data transmission, a third data transmission, and a fourth
data transmission are included from top to bottom.
Before the first data transmission, the transmit device may
separately calculate reliability of 16 polar channels, and sort the
16 polar channels from left to right in descending order of
reliability.
During the first data transmission, the transmit device may
determine 12 information bits based on a code rate R of the first
data transmission, add sequence numbers corresponding to 12 polar
channels (12 polar channels counting from the left) that have
highest reliability rankings into a set A.sub.1, and respectively
transmit, on the 12 polar channels represented by the set A.sub.1,
the 12 information bits: u.sub.1, u.sub.2, . . . , and
u.sub.12.
During the second data transmission, the transmit device may add,
based on a code rate R/2 of the second data transmission, sequence
numbers corresponding to six polar channels that have highest
reliability rankings into a set A.sub.2, and further determine
information bits mapped to
A.sub.1\A.sub.2={a.sub.i|a.sub.i.di-elect
cons.A.sub.1,a.sub.iA.sub.2} channels during the first data
transmission, that is, u.sub.7, u.sub.8, u.sub.9, u.sub.10,
u.sub.11, and u.sub.12. The information bits u.sub.7, u.sub.8,
u.sub.9, u.sub.10, u.sub.11, and u.sub.12 are separately mapped to
the polar channels represented by the set A.sub.2 for
transmission.
The determined code rate of the second data transmission is R/2
because when there is no feedback information from the receive
device, it is expected that a code rate of each transmission is
obtained through even division. For example, when the code rate of
the initial transmission is R, half of information bits are used
for retransmission in the first retransmission, and after one
retransmission, the code rates of the initial transmission and the
first retransmission are R/2. When channel quality of the initial
transmission and channel quality of the first retransmission are
the same, this policy of evenly dividing a code rate can ensure
that decoding success rates for the two transmissions are the same,
preventing a case in which decoding fails due to an excessively
high code rate of one transmission. Likewise, a code rate of each
subsequent data transmission may be determined.
Likewise, during the third data transmission, the transmit device
may add, based on a code rate R/3 of the third data transmission,
sequence numbers corresponding to four polar channels that have
highest reliability rankings into a set A.sub.3, further determine
information bits u.sub.5 and u.sub.6 mapped to
A.sub.2\A.sub.3={a.sub.i|a.sub.i.di-elect
cons.A.sub.2,a.sub.iA.sub.3} channels during the first data
transmission and information bits u.sub.11 and u.sub.12 mapped to
A.sub.2\A.sub.3={a.sub.i|a.sub.i.di-elect
cons.A.sub.2,a.sub.iA.sub.3} channels during the second data
transmission, and finally separately map an information bit
sequence u.sub.5, u.sub.6, u.sub.11, u.sub.12 to the polar channels
represented by the set A.sub.3 for transmission.
During the fourth data transmission, the transmit device may add,
based on a code rate R/4 of the fourth data transmission, sequence
numbers corresponding to three polar channels that have highest
reliability rankings into a set A.sub.4, further determine an
information bit u.sub.4 mapped to an
A.sub.3\A.sub.4={a.sub.i|a.sub.i.di-elect
cons.A.sub.3,a.sub.iA.sub.4} channel during the first data
transmission, an information bit u.sub.10 mapped to an
A.sub.3\A.sub.4={a.sub.i|a.sub.i.di-elect
cons.A.sub.3,a.sub.iA.sub.4} channel during the second data
transmission, and an information bit u.sub.12 mapped to an
A.sub.3\A.sub.4={a.sub.i|a.sub.i.di-elect
cons.A.sub.3,a.sub.iA.sub.4} channel during the third data
transmission, and finally separately map an information bit
sequence u.sub.4, u.sub.10, u.sub.12 to the polar channels
represented by the set A.sub.4 for transmission.
During each retransmission, information bits are mapped to the
first polar channel sequence strictly in an order of information
bits that need to be transmitted during the first data
transmission. FIG. 3 is used as an example. If the order of the
information bits that need to be transmitted during the first
transmission is u.sub.1, u.sub.2, . . . , and u.sub.12, an order of
information bits that need to be transmitted during the second
transmission is u.sub.7, u.sub.8, u.sub.9, u.sub.10, u.sub.11, and
u.sub.12, an order of information bits that need to be transmitted
during the third transmission is u.sub.5, u.sub.6, u.sub.11, and
u.sub.12, and an order of information bits that need to be
transmitted during the fourth transmission is u.sub.4, u.sub.10,
and u.sub.12. However, it should be understood that this is not
limited in this embodiment of this application, and a subsequent
retransmission may be performed in any other order. For example,
the order of the information bits that need to be transmitted
during the second transmission is u.sub.12, u.sub.11, . . . , and
u.sub.1, the order of the information bits that need to be
transmitted during the third transmission is u.sub.11, u.sub.12,
u.sub.9, and u.sub.6, and the order of the information bits that
need to be transmitted during the fourth transmission is u.sub.4,
u.sub.10, and u.sub.12. This is not limited in this embodiment of
this application.
It should be understood that a coding parameter for each data
transmission may be fixed or may be adaptively changed. This is not
limited in this embodiment of this application. Specifically, the
transmit device may determine, in a plurality of manners, the
coding parameter for each data transmission.
In an optional embodiment, the determining the coding parameter for
the m.sup.th data transmission includes:
determining a preset coding parameter as the coding parameter for
the m.sup.th data transmission.
Specifically, the preset coding parameter may be agreed on by the
transmit device and the receive device in advance, or may be
determined based on feedback information sent by the receive
device. In short, the preset coding parameter is fixed or is
determined according to a specific rule. In a specific
implementation, if the code rate of the initial transmission is R,
and the receive device and the transmit device agree on a rule of a
code rate of each retransmission in advance, the code rate of the
second transmission is
##EQU00024## the code rate of the third transmission is
##EQU00025## . . . , and a code rate of the m.sup.th transmission
is
##EQU00026##
In an optional embodiment, the determining the coding parameter for
the m.sup.th data transmission includes:
receiving feedback information sent by the receive device for the
(m-1).sup.th data transmission; and
determining the coding parameter for the m.sup.th data transmission
based on the feedback information for the (m-1).sup.th data
transmission.
In other words, during a data retransmission, a code length, a
retransmission code rate, or a quantity of information bits can be
determined based on quality of a channel for a previous data
transmission. The feedback information may include channel state
information (CSI), a signal to interference plus noise ratio
(SINR), or a channel quality indicator (CQI) in Long Term Evolution
(LTE); or may include a code rate directly sent by the receive
device; or may include a modulation and coding scheme (MCS), a
transmission resource size, or the like. The coding parameter
includes one or more parameters of a code length, a code rate, and
a quantity of information bits.
It should be understood that a quantity of encoded bits is a code
length. The two concepts are interchangeable in the embodiment of
this application. It should be further understood that a quantity
of information bits may be determined by using a code length and a
code rate, or a code rate may be determined by using a code length
and a quantity of information bits. In other words, a third
parameter may be deduced by using only two of the three parameters.
In addition, other information that can be used to instruct the
transmit device to determine the coding parameter shall fall within
the protection scope of the embodiments of this application.
Specifically, the feedback information may include a CQI or an
SINR. The CQI is used as an example. There is a mapping table
between a CQI and a code rate, so that the code rate may be
determined by using the CQI. In other words, an actually allowed
code rate on a channel during a previous transmission can be
determined from the received feedback information, and when a
transmission resource is unchanged, a code rate of a current
retransmission can be determined based on a code rate that can be
actually provided on a channel during the previous transmission.
Further, because the transmission resource is unchanged, a code
length is unchanged. Therefore, a quantity of information bits that
are retransmitted this time may be determined by using the code
rate and the code length.
Therefore, in this embodiment of this application, the transmit
device can adjust, by using the feedback information sent by the
receive device, a coding parameter such as a code rate, a code
length, or a quantity of information bits, so as to adaptively
change a code rate during a retransmission.
FIG. 4 is a schematic diagram of an encoder according to an
embodiment of this application. As shown in FIG. 4, M is a maximum
quantity of transmissions (including an initial transmission).
Specifically, bits that are encoded again each time include some
information bits during all previous data transmissions, and
information bits selected each time are information bits that are
restructured based on a current retransmission code rate and that
are corresponding to polar channels with lower reliability during
all the previous data transmissions. A specific process of
selecting an information bit is the same as that in the method
described in the foregoing embodiment. Details are not described
herein again.
FIG. 5 is a schematic flowchart of a polar code retransmission
method 300 according to an embodiment of this application. The
method 300 may be applied to the wireless communications system 100
in FIG. 1. However, this embodiment of this application is not
limited thereto. In addition, the method 300 may be performed by a
network device, or may be user equipment. As shown in FIG. 3, the
method 300 includes the following steps:
S310. Determine a first polar channel sequence including N polar
channels and reliability of each of the N polar channels.
S320. Determine, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate.
S330. Determine K.sub.m polar channels with highest reliability in
the first polar channel sequence.
S340. Decode, on the K.sub.m polar channels, data transmitted
during the m.sup.th data transmission.
Herein, m, K.sub.m, and N are positive integers, m is greater than
1, and K.sub.m is less than N.
Therefore, according to the polar code retransmission method in
this embodiment of this application, during each data transmission,
K.sub.m polar channels are directly determined by using the same
polar channel sequence, and received data is directly decoded on
the K.sub.m polar channels, without recalculating reliability of
the polar channels before each reception of data retransmitted by a
transmit device. This can reduce decoding complexity and improve
transmission performance, thereby improving user experience.
In an optional embodiment, the first polar channel sequence is
generated by sorting the N polar channels based on the reliability
of each of the N polar channels.
In an optional embodiment, the method further includes:
sending feedback information to a transmit device, so that the
transmit device determines the coding parameter for the m.sup.th
data transmission based on the feedback information.
In an optional embodiment, the reliability of each polar channel is
a polarization weight of the polar channel.
In an optional embodiment, before the determining a first polar
channel sequence including N polar channels and reliability of each
of the N polar channels, the method further includes:
calculating the polarization weight of each of the N polar
channels.
In an optional embodiment, the calculating the polarization weight
of each of the N polar channels includes:
obtaining the first polarization weight vector by calculating the
polarization weights W.sub.i of the N polar channels according to
the following formula:
.times..PHI..alpha. ##EQU00027##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
It should be understood that sequence numbers of the foregoing
processes do not mean particular execution sequences. The execution
sequences of the processes should be determined based on functions
and internal logic of the processes, and should not be construed as
any limitation on the implementation processes of the embodiments
of this application.
The foregoing describes in detail the polar code retransmission
method according to the embodiments of this application with
reference to FIG. 1 to FIG. 5. The following describes in detail a
polar code retransmission apparatus according to embodiments of
this application with reference to FIG. 6 to FIG. 9.
FIG. 6 is a schematic block diagram of a polar code retransmission
apparatus 400 according to an embodiment of this application. The
apparatus 400 includes:
a determining unit 410, configured to: determine a first polar
channel sequence including N polar channels and reliability of each
of the N polar channels;
determine, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate;
determine K.sub.m polar channels with highest reliability in the
first polar channel sequence; and
determine K.sub.m information bits based on locations, of
information bits that need to be transmitted during first m-1 data
transmissions, in the first polar channel sequence; and
a sending unit 420, configured to map the K.sub.m information bits
to the K.sub.m polar channels for transmission, where
m, K.sub.m, and N are positive integers, m is greater than 1, and
K.sub.m is less than N.
Therefore, according to the polar code retransmission apparatus in
this embodiment of this application, the same polar channel
sequence is used during each data transmission, and the determined
K.sub.m information bits are directly mapped to the K.sub.m polar
channels with highest reliability in the polar channel sequence for
transmission, without recalculating the reliability of the polar
channels before each retransmission. This can reduce retransmission
complexity and improve transmission performance, thereby improving
user experience.
Optionally, m is 2, and the K.sub.m information bits are
information bits that occupy K.sub.m polar channels with lowest
reliability in the first polar channel sequence during a first data
transmission.
Optionally, a code rate of the first data transmission is R, and a
code rate of the m.sup.th data transmission is
##EQU00028## where R is greater than 0 and less than 1. The
determining unit is specifically configured to: determine K.sub.m-1
polar channels, corresponding to information bits that need to be
transmitted during an (m-1).sup.th data transmission, in the first
polar channel sequence, where K.sub.m-1 is less than N and greater
than K.sub.m; determine
##EQU00029## polar channels with lowest reliability from the
K.sub.m-1 polar channels; and determine the K.sub.m information
bits from information bits on the
##EQU00030## polar channels during each of the first m-1 data
transmissions.
Optionally, the apparatus further includes: a sorting unit,
configured to sort the K.sub.m information bits in descending order
of reliability of the polar channels corresponding to the K.sub.m
information bits that need to be transmitted during the first data
transmission. The sending unit 420 is specifically configured to
map, for transmission, the sorted K.sub.m information bits to the
K.sub.m polar channels ranked in descending order of
reliability.
Optionally, the determining unit 410 is further configured to:
before determining, based on the coding parameter for the m.sup.th
data transmission, the quantity K.sub.m of information bits that
need to be transmitted during the m.sup.th data transmission,
determine the coding parameter for the m.sup.th data
transmission.
Optionally, the determining unit 410 is specifically configured to
determine a preset coding parameter as the coding parameter for the
m.sup.th data transmission.
Optionally, the apparatus further includes: a receiving unit,
configured to receive feedback information sent by a receive device
for the (m-1).sup.th data transmission. The determining unit 410 is
specifically configured to determine the coding parameter for the
m.sup.th data transmission based on the feedback information for
the (m-1).sup.th data transmission.
Optionally, the first polar channel sequence is generated by
sorting the N polar channels based on the reliability of each of
the N polar channels.
Optionally, the reliability of each polar channel is a polarization
weight of the polar channel.
Optionally, the apparatus further includes: a calculation unit,
configured to: before the first polar channel sequence including
the N polar channels and the reliability of each of the N polar
channels are determined, calculate the polarization weight of each
of the N polar channels.
Optionally, the calculation unit is specifically configured to
obtain the first polarization weight vector by calculating the
polarization weights W.sub.i of the N polar channels according to
the following formula:
.times..PHI..alpha. ##EQU00031##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
It should be understood that the apparatus 400 herein is embodied
in a form of functional units. The term "unit" herein may be an
application-specific integrated circuit (application-specific
integrated circuit, ASIC), an electronic circuit, a processor (for
example, a shared processor, a dedicated processor, or a group
processor) configured to execute one or more software or firmware
programs and a memory, a combinational logic circuit, and another
appropriate component that supports the described functions. In an
optional example, a person skilled in the art may understand that
the apparatus 400 may be specifically the transmit device in the
foregoing embodiments, and the apparatus 400 may be configured to
perform procedures and steps that are corresponding to the transmit
device in the foregoing method embodiments. To avoid repetition,
details are not described herein again.
FIG. 7 is a schematic block diagram of a polar code retransmission
apparatus 500 according to an embodiment of this application. The
apparatus 500 includes:
a determining unit 510, configured to: determine a first polar
channel sequence including N polar channels and reliability of each
of the N polar channels;
determine, based on a coding parameter for an m.sup.th data
transmission, a quantity K.sub.m of information bits that need to
be transmitted during the m.sup.th data transmission, where the
coding parameter includes at least one of the quantity of
information bits and a code rate; and
determine K.sub.m polar channels with highest reliability in the
first polar channel sequence; and
a decoding unit 520, configured to decode, on the K.sub.m polar
channels, data transmitted during the m.sup.th data transmission,
where
m, K.sub.m, and N are positive integers, m is greater than 1, and
K.sub.m is less than N.
Therefore, according to the polar code retransmission apparatus in
this embodiment of this application, during each data transmission,
K.sub.m polar channels are directly determined by using the same
polar channel sequence, and received data is directly decoded on
the K.sub.m polar channels, without recalculating reliability of
the polar channels before each reception of data retransmitted by a
transmit device. This can reduce decoding complexity and improve
transmission performance, thereby improving user experience.
Optionally, the first polar channel sequence is generated by
sorting the N polar channels based on the reliability of each of
the N polar channels.
Optionally, the apparatus further includes:
a sending unit, configured to send feedback information to a
transmit device, so that the transmit device determines the coding
parameter for the m.sup.th data transmission based on the feedback
information.
Optionally, the reliability of each polar channel is a polarization
weight of the polar channel.
Optionally, the apparatus further includes: a calculation unit,
configured to: before the first polar channel sequence including
the N polar channels and the reliability of each of the N polar
channels are determined, calculate the polarization weight of each
of the N polar channels.
Optionally, the calculation unit is specifically configured to
obtain the first polarization weight vector by calculating the
polarization weights W.sub.i of the N polar channels according to
the following formula:
.times..PHI..alpha. ##EQU00032##
where iB.sub.n-1B.sub.n-2 . . . B.sub.0, i is a channel index,
B.sub.n-1B.sub.n-2 . . . B.sub.0 is a binary representation of i,
B.sub.n-1 is a most significant bit, B.sub.0 is a least significant
bit, B.sub.j.di-elect cons.{0,1}, j.di-elect cons.{0, 1, . . . ,
n-1}, i.di-elect cons.{0, 1, . . . , n-1}, N=2.sup.n, .PHI. and
.alpha. are parameters preset based on a target code length of a
first data transmission and a code rate of the first data
transmission, and n is a positive integer.
It should be understood that the apparatus 500 herein is embodied
in a form of functional units. The term "unit" herein may be an
application-specific integrated circuit (application-specific
integrated circuit, ASIC), an electronic circuit, a processor (for
example, a shared processor, a dedicated processor, or a group
processor) configured to execute one or more software or firmware
programs and a memory, a combinational logic circuit, and another
appropriate component that supports the described functions. In an
optional example, a person skilled in the art may understand that
the apparatus 500 may be specifically the receive device in the
foregoing embodiments, and the apparatus 500 may be configured to
perform procedures and steps that are corresponding to the receive
device in the foregoing method embodiments. To avoid repetition,
details are not described herein again.
FIG. 8 shows a polar code retransmission apparatus 600 according to
an embodiment of this application. The apparatus 600 includes a
processor 610, a transceiver 620, a memory 630, and a bus system
640. The processor 610, the transceiver 620, and the memory 630 are
connected by using the bus system 640, the memory 630 is configured
to store an instruction, and the processor 610 is configured to
execute the instruction stored in the memory 630, to control the
transceiver 620 to send a signal and receive a signal.
The processor 610 is configured to: determine a first polar channel
sequence including N polar channels and reliability of each of the
N polar channels; determine, based on a coding parameter for an
m.sup.th data transmission, a quantity K.sub.m of information bits
that need to be transmitted during the m.sup.th data transmission,
where the coding parameter includes at least one of the quantity of
information bits and a code rate; determine K.sub.m polar channels
with highest reliability in the first polar channel sequence;
determine K.sub.m information bits based on locations, of
information bits that need to be transmitted during first m-1 data
transmissions, in the first polar channel sequence; and instruct
the transceiver 620 to map the K.sub.m information bits to the
K.sub.m polar channels for transmission, where m, K.sub.m, and N
are positive integers, m is greater than 1, and K.sub.m is less
than N.
It should be understood that the apparatus 600 may be specifically
the transmit device in the foregoing embodiments, and may be
configured to perform steps and/or procedures that are
corresponding to the transmit device in the foregoing method
embodiments. Optionally, the memory 630 may include a read-only
memory and a random access memory, and provide an instruction and
data for the processor. A part of the memory may further include a
non-volatile random access memory. For example, the memory may
further store information about a device type. The processor 610
may be configured to execute the instruction stored in the memory.
When the processor executes the instruction stored in the memory,
the processor is configured to perform the steps and/or the
procedures that are corresponding to the transmit device in the
foregoing method embodiments.
FIG. 9 shows a polar code retransmission apparatus 700 according to
an embodiment of this application. The apparatus 700 includes a
processor 710, a transceiver 720, a memory 730, and a bus system
740. The processor 710, the transceiver 720, and the memory 730 are
connected by using the bus system 740, the memory 730 is configured
to store an instruction, and the processor 710 is configured to
execute the instruction stored in the memory 730, to control the
transceiver 720 to send a signal and receive a signal.
The processor 710 is configured to: determine a first polar channel
sequence including N polar channels and reliability of each of the
N polar channels; determine, based on a coding parameter for an
m.sup.th data transmission, a quantity K.sub.m of information bits
that need to be transmitted during the m.sup.th data transmission,
where the coding parameter includes at least one of the quantity of
information bits and a code rate; determine K.sub.m polar channels
with highest reliability in the first polar channel sequence; and
decode, on the K.sub.m polar channels, data transmitted during the
m.sup.th data transmission, where m, K.sub.m, and N are positive
integers, m is greater than 1, and K.sub.m is less than N.
It should be understood that the apparatus 700 may be specifically
the receive device in the foregoing embodiments, and may be
configured to perform steps and/or procedures that are
corresponding to the receive device in the foregoing method
embodiments. Optionally, the memory 730 may include a read-only
memory and a random access memory, and provide an instruction and
data for the processor. A part of the memory may further include a
non-volatile random access memory. For example, the memory may
further store information about a device type. The processor 710
may be configured to execute the instruction stored in the memory.
When the processor executes the instruction stored in the memory,
the processor is configured to perform the steps and/or the
procedures that are corresponding to the receive device in the
foregoing method embodiments.
It should be understood that in the embodiments of this
application, the processor may be a central processing unit (CPU),
or the processor may be another general purpose processor, a
digital signal processor (DSP), an application-specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or another
programmable logic device, a discrete gate or transistor logic
device, a discrete hardware component, or the like. The general
purpose processor may be a microprocessor, or the processor may be
any conventional processor or the like.
In an implementation process, each step of the foregoing method may
be completed by using an integrated logical circuit of hardware in
the processor or an instruction in a form of software. The steps of
the methods disclosed with reference to the embodiments of this
application may be directly performed and completed by a hardware
processor, or may be performed and completed by using a combination
of hardware and software modules in the processor. A software
module may be located in a mature storage medium in the art, such
as a random access memory, a flash memory, a read-only memory, a
programmable read-only memory, an electrically erasable
programmable memory, a register, or the like. The storage medium is
located in the memory, and the processor executes instructions in
the memory and completes the steps in the foregoing methods in
combination with hardware of the processor. To avoid repetition,
details are not described herein again.
FIG. 10 and FIG. 11 each are a schematic diagram of transmission
performance of a polar code retransmission method according to an
embodiment of this application.
In the retransmission method in the embodiments of this
application, a polar channel sequence needs to be constructed only
once. However, in a method used for comparison, for each HARQ
retransmission, reliability of a polar channel needs to be
calculated and a polar channel sequence needs to be reconstructed.
The following gives specific parameters for simulation and
comparison. The specific parameters are as follows: On an additive
white Gaussian noise (AWGN) channel, a given code length is 8000, a
code rate is and 8/9, and a modulation order is 6.
FIG. 10 and FIG. 11 each show analog curves of four transmissions.
It can be seen from the analog curves that performance of the
technical solutions proposed in the embodiments of this application
is close to performance of the prior art, and a performance
difference falls within a range of 0.1 dB to 0.2 dB on the AWGN
channel. However, the solutions proposed in the embodiments of this
application are of low complexity, are easy to operate, and can
improve transmission performance.
It should be understood that "one embodiment" or "an embodiment"
mentioned in the whole specification means that particular
features, structures, or characteristics related to the embodiment
are included in at least one embodiment of this application.
Therefore, "in one embodiment" or "in an embodiment" appearing
throughout the specification does not refer to a same embodiment.
Moreover, the particular characteristic, structure or property may
be combined in one or more embodiments in any proper manner. It
should be understood that sequence numbers of the foregoing
processes do not mean particular execution sequences in various
embodiments of this application. The execution sequences of the
processes should be determined based on functions and internal
logic of the processes, and should not be construed as any
limitation on the implementation processes of the embodiments of
this application.
In addition, the terms "system" and "network" may be used
interchangeably in this specification. The term "and/or" in this
specification describes only an association relationship for
describing associated objects and represents that three
relationships may exist. For example, A and/or B may represent the
following three cases: Only A exists, both A and B exist, and only
B exists. In addition, the character "/" in this specification
usually indicates an "or" relationship between the associated
objects.
It should be understood that in the embodiments of this
application, "B corresponding to A" indicates that B is associated
with A, and B may be determined based on A. However, it should be
further understood that determining B based on A does not mean that
B is determined based on A only; that is, B may also be determined
based on A and/or other information.
A person of ordinary skill in the art may be aware that, the units
and steps in the examples described with reference to the
embodiments disclosed herein may be implemented by electronic
hardware, computer software, or a combination thereof. To clearly
describe the interchangeability between the hardware and the
software, the foregoing has generally described compositions and
steps of each example based on functions. Whether the functions are
performed by hardware or software depends on particular
applications and design constraint conditions of the technical
solutions. A person skilled in the art may use different methods to
implement the described functions for each particular application,
but it should not be considered that the implementation goes beyond
the scope of this application.
It may be clearly understood by a person skilled in the art that,
for the purpose of convenient and brief description, for a detailed
working process of the foregoing system, apparatus, and unit, refer
to a corresponding process in the foregoing method embodiments, and
details are not described herein.
In the several embodiments provided in this application, it should
be understood that the disclosed system, apparatus, and method may
be implemented in other manners. For example, the described
apparatus embodiment is merely an example. For example, the unit
division is merely logical function division and may be other
division in actual implementation. For example, a plurality of
units or components may be combined or integrated into another
system, or some features may be ignored or not performed. In
addition, the displayed or discussed mutual couplings or direct
couplings or communication connections may be implemented through
some interfaces, indirect couplings or communication connections
between the apparatuses or units, or electrical connections,
mechanical connections, or connections in other forms.
The units described as separate parts may or may not be physically
separate, and parts displayed as units may or may not be physical
units, may be located in one position, or may be distributed on a
plurality of network units. Some or all of the units may be
selected based on actual needs to achieve the objectives of the
solutions of the embodiments of this application.
In addition, functional units in the embodiments of this
application may be integrated into one processing unit, or each of
the units may exist alone physically, or two or more units are
integrated into one unit. The integrated unit may be implemented in
a form of hardware, or may be implemented in a form of a software
functional unit.
With descriptions of the foregoing implementations, a person
skilled in the art may clearly understand that this application may
be implemented by hardware, firmware or a combination thereof. When
this application is implemented by software, the foregoing
functions may be stored in a computer-readable medium or
transmitted as one or more instructions or code in the
computer-readable medium. The computer-readable medium includes a
computer storage medium and a communications medium, where the
communications medium includes any medium that enables a computer
program to be transmitted from one place to another. The storage
medium may be any available medium accessible to a computer. For
example but not for limitation, the computer-readable medium may
include a RAM, a ROM, an EEPROM, a CD-ROM, or another optical disc
storage or disk storage medium, or another magnetic storage device,
or any other medium that can carry or store expected program code
in a form of an instruction or a data structure and can be accessed
by a computer. In addition, any connection may be appropriately
defined as a computer-readable medium. For example, if software is
transmitted from a website, a server, or another remote source by
using a coaxial cable, an optical fiber/cable, a twisted pair, a
digital subscriber line (DSL), or wireless technologies such as
infrared ray, radio, and microwave, the coaxial cable, optical
fiber/cable, twisted pair, DSL, or wireless technologies such as
infrared ray, radio, and microwave are included in a definition of
the medium. As used in this application, disks (Disk) and discs
(disc) include a compact disc (CD), a laser disc, an optical disc,
a digital versatile disc (DVD), a floppy disk, and a Blu-ray disc.
The disk usually copies data by a magnetic means, and the disc
optically copies data by a laser means. The foregoing combination
should also be included in the protection scope of the
computer-readable medium.
In conclusion, the foregoing descriptions are merely examples of
embodiments of the technical solutions of this application, but are
not intended to limit the protection scope of this application. Any
modification, equivalent replacement, or improvement made without
departing from the principle of this application shall fall within
the protection scope of this application.
* * * * *